1. Field of the Invention
The present invention is related to an antenna and particularly to a multi-band antenna.
2. Description of Related Art
With recent advancements of technologies, communication methods of the public are gradually changed to wireless communications, devices such as a smart phone, a tablet PC capable of surfing the Internet and a notebook computer all fall within the scope of wireless communications, in which an antenna is required for transmitting signal.
Planar Inverted-F Antenna (PIFA) is one of the most commonly seen antenna, such antenna has a fundamental mode that operates in a quarter of wave length thereby reducing a length of the antenna, which meets the compact and requirement of modern electronic products. However, as design trend of electronic devices being lighter and thinner each day, if the electronic device is provided with metal shell, it is difficult to have the antenna disposed far from the metal shell, such that signal of the antenna may be interfered by the metal shell. Take notebook computer for instance, if an antenna is disposed on the display screen while the host is made of metal shell, once a user have the display screen closed on the host, a signal interference may occur to the antenna for being to close to the metal shell of the host.